Shewan D, Berry M, Bedi K, Cohen J
Division of Anatomy and Cell Biology, UMDS, London, UK.
Eur J Neurosci. 1993 Jul 1;5(7):809-17. doi: 10.1111/j.1460-9568.1993.tb00932.x.
The failure of axon regeneration in the injured mammalian central nervous system has been ascribed, in part, to the inhibitory effects of myelin proteins. To investigate the influence of myelination on neurite growth and regeneration by both central nervous system and peripheral nervous system neurons, isolated rat neonatal retinal ganglion cells and adult and neonatal dorsal root ganglion neurons were cultured on cryostat sections of both immature unmyelinated and mature fully myelinated adult rat optic nerve. In agreement with earlier studies using neonatal peripheral neurons, the adult optic nerve failed to support neurite outgrowth from any of the neurons tested. A new finding was that tissue sections from unmyelinated optic nerve (aged embryonic days 18 and 20, and postnatal days 1-3), also failed to support the growth of neurites from neonatal retinal ganglion cells and both neonatal and adult dorsal root ganglion neurons. Neonatal retinal ganglion cells also failed to extend neurites on sections of pre-degenerated sciatic nerve, a tissue shown in our previous work to be a good substratum for supporting neurite growth for both neonatal and adult DRG neurons. These results suggest that cells in the immature optic nerve either express widely acting axon growth inhibitory molecules unrelated to previously described myelin proteins, or do not synthesize appropriate axon growth promoting molecules. They also reveal that, for axon regeneration, central nervous system and peripheral sensory neurons require distinct substratum interactions.
哺乳动物中枢神经系统损伤后轴突再生失败，部分原因被认为是髓磷脂蛋白的抑制作用。为了研究髓鞘形成对中枢神经系统和周围神经系统神经元神经突生长及再生的影响，将新生大鼠视网膜神经节细胞以及成年和新生大鼠背根神经节神经元，培养在未成熟无髓鞘和成熟完全髓鞘化的成年大鼠视神经的冷冻切片上。与早期使用新生周围神经元的研究一致，成年视神经无法支持所测试的任何神经元长出神经突。一个新发现是，未髓鞘化视神经（胚胎第18和20天以及出生后第1 - 3天）的组织切片，也无法支持新生大鼠视网膜神经节细胞以及新生和成年大鼠背根神经节神经元的神经突生长。新生大鼠视网膜神经节细胞在预先变性的坐骨神经切片上也无法延伸神经突，我们之前的研究表明，坐骨神经组织是支持新生和成年背根神经节神经元神经突生长的良好基质。这些结果表明，未成熟视神经中的细胞要么表达与先前描述的髓磷脂蛋白无关的广泛作用的轴突生长抑制分子，要么不合成适当的轴突生长促进分子。它们还揭示，对于轴突再生，中枢神经系统和周围感觉神经元需要不同的基质相互作用。
